Small PCB trim pot knobs?

[kalel]

These things can be quite cheap:



and might be accurate enough for some adjustments. In fact, you get them on Chinese buck boost voltage regulators and such. If you're actively adjusting the voltage it could be a bit annoying.

Obviously they are designed to be adjusted with a tool, but for convenience, do you know if caps for this exist or could be improvised from something?

[rdl]

I have some Bourns trimmers that have knobs long enough for finger adjustment which are handy for breadboard circuits. I don't know if they have similar multi-turn types though.

[sleemanj]

Yes there are tools you can get, like a shrouded screwdriver in the style of a pen...

https://www.google.co.nz/search?safe=off&biw=1680&bih=960&tbm=isch&q=trimmer+adjustment+tool&oq=trimmer+adjustment+tool&gs_l=psy-ab.3..0.3307.4607.0.4760.11.8.0.0.0.0.247.478.2-2.2.0....0...1.1.64.psy-ab..9.2.477...0i5i30k1j0i8i30k1.mtgBdV9SnYs&gws_rd=cr&ei=2pqTWfjaHoGS8wWbmqdo#gws_rd=cr&imgrc=-7oMF4XQE45g8M:

Or, find some tube about the right diameter, and a screwdriver, and shroud it yourself :-)

[sleemanj]

You can also get trimpots with knobs, I don't recall seeing them in the tall (3296) type, but in the flat type....

https://www.google.co.nz/search?safe=off&biw=1680&bih=960&tbm=isch&sa=1&q=trimpot+&oq=trimpot+&gs_l=psy-ab.3..0i67k1j0j0i67k1j0.13164.14085.0.14489.8.7.0.0.0.0.267.267.2-1.1.0....0...1.1.64.psy-ab..7.1.266.vzZ6To2820k#imgrc=O85he_JxrYYEQM:

[w2aew]

One of the main reasons that trimpots don't generally come with knobs is because they have a very limited rotational life and should not be used in applications where they'd be operated a lot (like a control).

[cvanc]

One of the main reasons that trimpots don't generally come with knobs is because they have a very limited rotational life and should not be used in applications where they'd be operated a lot (like a control).

Yeah, this.  Even some of the good ones are rated surprisingly low in this regard.  Should be in the datasheet.

[kalel]

One of the main reasons that trimpots don't generally come with knobs is because they have a very limited rotational life and should not be used in applications where they'd be operated a lot (like a control).

Yes, that seems quite reasonable. But for some uses, quick breadboard experimentation or other experimentation, and them coming with some stepdowns and stepups makes you want to have a simple way of adjusting without needing to have an adjustment tool or screwdriver with you every time (as an example, I'm using a step down that has one of those for adjustment and a built in voltmeter as an improvised voltage controlled power supply).

They are also smaller and significantly cheaper than larger potentiometers designed to be frequently adjusted. For a finished product, it definitely makes sense to use the proper part and consider longevity and definitely other specs too.

Maybe a cap could be improvised? Some tube or something, and a little bit of glue. Maybe heatshrink and a bit of heat? The issue with many kinds of glue and trying to glue something to the screw is that it might leak between the screw and plastic and have the undesirable effect of also fixing the position, so that you can't rotate it at all. Trying to apply a small amount of hot melt glue over the screw might work, but I doubt it sticks that great to metal.

[T3sl4co1l]

I've done this before: tack some trimmers onto a piece of copper clad, with the surface cut up into islands for each connection as needed.  Jumper the pads down to a header.  Plug the header into the solderless breadboard.

That avoids the trouble of leads that are too short, floopy, or the wrong pitch, and allows you to use SMTs, too.

I'm not sure what this has to do with trimmer capacitors...

Tim

[kalel]

I've done this before: tack some trimmers onto a piece of copper clad, with the surface cut up into islands for each connection as needed.  Jumper the pads down to a header.  Plug the header into the solderless breadboard.

That avoids the trouble of leads that are too short, floopy, or the wrong pitch, and allows you to use SMTs, too.

I'm not sure what this has to do with trimmer capacitors...

Tim

By caps in the title, I meant knobs actually (well plastic or other caps over the trim pot, making them easier or at least possible to rotate using fingers alone). Might be using the wrong term.

[tautech]

I've done this before: tack some trimmers onto a piece of copper clad, with the surface cut up into islands for each connection as needed.  Jumper the pads down to a header.  Plug the header into the solderless breadboard.

That avoids the trouble of leads that are too short, floopy, or the wrong pitch, and allows you to use SMTs, too.

I'm not sure what this has to do with trimmer capacitors...

Tim

By caps in the title, I meant knobs actually (well plastic or other caps over the trim pot, making them easier or at least possible to rotate using fingers alone). Might be using the wrong term.

It might read better if you use the word: knob.......I did a doubletake but after reading the OP again I understood you wanted knobs.

You can go back and edit the thread title. 

[kalel]

I've done this before: tack some trimmers onto a piece of copper clad, with the surface cut up into islands for each connection as needed.  Jumper the pads down to a header.  Plug the header into the solderless breadboard.

That avoids the trouble of leads that are too short, floopy, or the wrong pitch, and allows you to use SMTs, too.

I'm not sure what this has to do with trimmer capacitors...

Tim

By caps in the title, I meant knobs actually (well plastic or other caps over the trim pot, making them easier or at least possible to rotate using fingers alone). Might be using the wrong term.

It might read better if you use the word: knob.......I did a doubletake but after reading the OP again I understood you wanted knobs.

You can go back and edit the thread title. 

Right, I've changed the title.

[Brumby]

Personally, I wouldn't use trimpots on a breadboard setup unless lead length is an issue.  I have a panel with 1k and 10k linear pots plus a 100K log pot with some pin header sockets mounted for connection points.

[Le_Bassiste]

Clippy's Final Destination 

[IanMacdonald]

These are the best thing...

http://uk.rs-online.com/web/p/trimmer-tools/0543434/

[tggzzz]

These are the best thing...

http://uk.rs-online.com/web/p/trimmer-tools/0543434/

I'm still using one like that I bought ~40 years ago.

[Raj]

You'll have to be creative and stick a small tube to the knob, which later is turned using a bigger knob

[kalel]

Trim tool might even be the best thing in the end, but other creative solutions are great too.

[FlyingHacker]

If the goal is a knob for breadboarding why not just use a regular pot? They are pretty cheap from China. They already have a knurled knob of sorts (and can take a real knob). They also fit right into a breadboard vertically.